The present invention relates to a fuel injection pump, especially for use in spark plug ignited internal combustion engines, wherein the injection quantity regulating member (control rod) is actuated by an r.p.m.-dependent centrifugal force governor acting through a lever linkage and via an interposed cam plate element.
In a known fuel injection pump of this type, the cam plate element is a member whose position depends on the position of the accelerator pedal, as well as on the position of the centrifugal weights rotated by the engine. When this known control mechanism is used, however, in low-load operation of the engine, i.e., when the accelerator pedal is only slightly depressed and in a region of low engine r.p.m., the air quantity aspirated by the engine may change without sufficiently precise fuel metering. In addition, the linkage mechanism in that system is also very complicated.
Another known control system in which the pressure within the induction tube is measured by means of a pressure sensor or pick-up system and correspondingly determines the position of the control rod, brings the disadvantage that the sensitivity becomes very poor at full-load operation, i.e., when the difference between the induction tube vacuum and the atmospheric pressure is very small.